Key Volatile Compounds Signifying Unpleasant Rubber Odor in Green Papaya (Carica papaya L.)

Unpleasant odors are crucial in terms of consumer acceptance. However, the volatile compounds responsible for the unpleasant rubbery odor in green papaya have not been thoroughly documented. Therefore, the primary objective of this study was to identify these key volatile compounds and examine how they are influenced by different papaya cultivars, harvest seasons, and fruit maturity stages. Using gas chromatography-olfactometry (GC-O), five odorants were identified as having a rubbery odor, with benzyl isothiocyanate and 2-cyclohexen-1-one showing a significant positive correlation with rubber-like odor scores (r > 0.8). In the ‘Khaek Nuan’ cultivar, known for its strong rubber odor, the intensity of the rubber odor and the concentrations of (E)-1,2-cyclohexanediol were higher in cool season fruits and at the immature stage. Conversely, the ‘Yellow Flesh’ cultivar, which has a mild rubber odor, exhibited no significant effect of season or maturity on the unpleasant rubber odor or the presence of benzyl isothiocyanate and (E)-1,2-cyclohexanediol. By specifically targeting these odorants, effective strategies can be developed to mitigate or minimize the unpleasant smell through approaches such as genetic modification, management practices, or postharvest interventions.